JPS59138758A - Piston ring and method of manufacturing thereof - Google Patents

Abstract

PURPOSE:To obtain a piston ring which is made of a cheap base material but has the properties of high seizing-resistance, scuffing-resistance and wear-resistance, by coating a wear-resistant material to an annular groove formed in the center section of the outer peripheral surface of the piston ring, and as well by forming a flame sprayed layer on the associated part of the annular groove. CONSTITUTION:An annular groove 5 is formed in the center section of the outer peripheral surface of a steel piston ring base material 1 during the drawing process of the latter, and a chromium plated layer 3 is coated on the outer peripheral surface of the base metal 1 which is then subjected to the flame spraying of a metal such as, for example, Mo, Ni, Cr or Fe, to form a flame sprayed layer 4 after being subjected to a shot-blast step. By polishing the flame sprayed layer 4 with the use of a grinding stone 5, the adjacent boundary section is removed to expose the chromium layer 3 in a slightly tapered shape, and the flame sprayed layer 4 is left only in the annular grooves 2 so that it projects largely more than both side sections 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piston ring for internal combustion, and more particularly to an improvement in an inlaid thermal sprayed ring having a thermal sprayed layer in an annular groove formed along its outer circumferential surface.

Among piston rings, especially for top rings that are subjected to a large thermal load, thermal sprayed rings are often used, which tend to contain metals having various properties on the sliding surface. However, conventionally, in-side spray rings have an annular shape with a sprayed layer formed on them. Since the base material is exposed on both sides of A', that is, on the upper and lower parts of the sliding surface, there is a possibility that this base material will come into sliding contact with the cylinder bore, which may cause scuffing and wear. For this reason, it is not possible to freely select the base material of the inlaid thermal spray ring, and cast iron, which is compatible with the bore, is widely used. However, when an inlaid thermal spray ring is manufactured from cast iron, there is a problem in that the manufacturing cost increases due to the necessity of machining an annular groove in which to embed the thermal spray layer.

On the other hand, Cylinder d? is a steel ring that does not require special groove processing and is highly productive in mass quantities. Its application is limited because it is generally not compatible with bores and tends to cause bore scuffing, 9-hole threads, etc.

The present invention aims to make it possible to manufacture an inlaid thermal sprayed ring that has sufficient performance in terms of seizure resistance, scuff resistance, wear resistance, etc. using an inexpensive base material such as steel. It was done for a purpose.

In the first invention, an annular groove is carved along the center part of the outer peripheral surface. The present invention provides a piston ring characterized in that its outer circumferential surface is coated with a wear-resistant material, and a thermally sprayed layer is formed in a portion corresponding to the annular groove.

A second invention relates to the method for manufacturing the piston ring,
This manufacturing method consists of a groove machining process in which an annular groove is carved along the center of the outer peripheral surface of an annularly formed material, a coating process in which the outer peripheral surface is coated with a wear-resistant material, and a wear-resistant material. a thermal spraying step of forming a sprayed layer on the outer peripheral surface coated with the material; and a polishing step of removing the entire thermal sprayed layer on the side of the annular groove to expose the wear-resistant material on the side. It is characterized by performing sequentially.

The present invention will be explained below with reference to illustrated embodiments.

During the drawing process, a steel wire rod is formed with grooves on one side, and then bent into an annular shape with the grooves on the outside and cut. As shown in FIG. 1, the annularly formed ring member 1 has an annular groove 2 along the center of its outer peripheral surface. Next, this ring member 1, as shown in FIG.
Is the outer circumferential surface made of wear-resistant material and the cylinder? A chrome plating layer 3 that is compatible with A is coated.

As shown in FIG. 3, the ring member 1 coated with the chrome plating layer 3 is formed into a cylindrical body by polymerizing a plurality of ring members 1, and is fitted and supported by a rod-shaped holder (not shown). After shot blasting, the outer peripheral surface of this cylindrical body, that is, the surface of the chrome plating layer 3, is coated with Mo, Ni,
A metal such as Cr + Fe is sprayed to form a sprayed layer 4 .

This sprayed layer 4 is polished by contacting it with a grindstone 5 while rotating it around its axis, and as shown in FIG. 3 is exposed.

The whetstone 5 has an annular raised portion 6 formed in a portion corresponding to this boundary portion in order to sharpen this boundary portion more sharply. During the polishing process of the ring member 1, not only the thermal sprayed layer at the boundary but also the chrome plating layer 3 are slightly polished, and as a result, the chrome plating layer 3 on both sides of the annular groove 5 has a slightly angular shape. The thermal sprayed layer 4id remains only in the annular groove 2 and protrudes from both sides.

- After the above-mentioned polishing process, a parel lazo process is performed, and the surface of the sprayed layer 4 is formed into a bun shape as shown in FIG.

FIG. 6 schematically shows an apparatus for carrying out the thermal lapping process. A support rod 8 is provided on the shaft center so as to be vertically movable and rotatable, and a pair of restraining plates 9 are fixed to the support rod 8 and are inclined in mutually opposite directions. It has lO. The ring member 1 is fitted onto the support rod 8 between these restraining plates 9 and 10. Therefore, when the support rod 8 is raised and lowered while rotating around its axis, when descending, the ring member 1 rotates while being inclined following the upper restraining plate 9, and conversely, when ascending, the ring member 1 rotates while being inclined, following the upper restraining plate 9. It rotates while being inclined following the plate 10. As a result,
The sprayed layer 4 is formed into a bun shape by slidingly contacting the hole 7.

It goes without saying that the angle of inclination of the restraining plates 9 and 10 and the diameter of the hole 7 are set to a size that does not substantially remove the chromium plating layer 3 on both sides of the sprayed layer 4. be.

In the piston ring manufactured as described above, tapered chrome layers 3 are formed on the base material surface above and below the sliding surface, and the thermal sprayed layer 4 is most protruding.

Therefore, even if the bending area of this ring becomes large during operation and parts other than the sprayed layer 4 come into contact with the cylinder gear, d
? It does not cause asuka 7 etc. and can significantly improve durability compared to conventional inlaid thermal sprayed rings.

In the above embodiment, a shot blasting process is performed before the thermal spraying process, but if the adhesion strength of the thermal sprayed layer 4 to the chromium plating layer 3 is sufficient, this shot blasting process can be omitted. That is, there are many micropores on the surface of the base material, and a large number of holes are formed on the surface of the chromium plating layer 30 in accordance with the micropores.

1. If there is a risk that the plating layer 3 will wear excessively due to ring tilt due to wear on the top and bottom surfaces of the piston ring, use SUS-based steel as the base material and apply Tuftride treatment to the top and bottom surfaces. It is preferable to apply

Further, the plating layer 3 may be formed by composite plating, or Teflon may be applied instead of the plating layer.

It goes without saying that the present invention can also be applied to keystone rings.

As described above, the present invention has the advantage that it is possible to obtain an inexpensive inlaid thermal spray ring with sufficient durability.

[Brief explanation of the drawing]

Fig. 1 1l-1' Ring member 1 immediately after forming the annular groove
2 is a cross-sectional view of the main part showing the ring member 1 immediately after being coated with the chrome plating layer, FIG. 3 is a partial cross-sectional side view showing the polishing process, and FIG. 4 is the polishing process. FIG. 5 is a cross-sectional view of the main parts showing the ring member after the process, FIG. 5 is a cross-sectional view of the main parts showing a piston ring according to an embodiment of the invention, and FIG. be. 2. Annularity, 3. Chrome plating layer, 4. Sprayed layer. 1st figure l-g, sH, 2nd figure 4 layers;, older brother 6, ゛ε

Claims (1)

[Claims] 1. An annular groove is carved along the center of the outer circumferential surface, and the outer circumferential surface is coated with an abrasion-resistant material, and a thermal sprayed layer is provided on the corresponding part of the annular groove. A piston ring characterized by being formed with. 2. The piston ring according to claim 1, wherein the thermally sprayed layer substantially protrudes from both side portions of the sprayed layer. 3. Grooving step of carving an annular groove along the center of the outer circumferential surface of the annularly formed material, coating step of coating the outer circumferential surface with a wear-resistant material, and coating the wear-resistant material. a thermal spraying step of forming a thermal sprayed layer on the outer peripheral surface of the thermally sprayed layer, and a polishing step of removing the thermal sprayed layer on the side of the annular groove to expose the wear-resistant material on the side. A method of manufacturing a piston ring, characterized in that: 4. The method of manufacturing a piston ring according to claim 3, wherein after the polishing step, a step of forming the sprayed layer surface in the annular groove into a bundling shape is performed.